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In SQLAlchemy, how can I make this conditional query on a child relationship?
class Parent(Base):
    __tablename__ = 'parent'
    __table_args__ = {
        UniqueConstraint("name", "version")
        }

    name = Column(String, primary_key=True)
    parent = Column(JSONEncodedDict)
    tags = relationship(ParentTags)
    version = Column(Integer)

class ParentTags(Base)::

    __tablename__ = 'parent_tags'
    __table_args__ = {
        UniqueConstraint("name", "tag"),
        }

    id = Column(Integer, Sequence("parent_tag_id_seq"), primary_key=True)
    name = Column(String, ForeignKey("parent.name"))
    tag = Column(String)
    version = Column(Integer)

session.query(Parent.name, Parent.version).
              join(ParentTag).
              filter(ParentTag.tag=='Production').
              all()